base/pending_task.h

   1 // Copyright (c) 2011 The Chromium Authors. All rights reserved.
   2 // Use of this source code is governed by a BSD-style license that can be
   3 // found in the LICENSE file.
   4
   5 #ifndef BASE_PENDING_TASK_H_
   6 #define BASE_PENDING_TASK_H_
   7
   8 #include <queue>
   9
  10 #include "base/base_export.h"
  11 #include "base/callback.h"
  12 #include "base/location.h"
  13 #include "base/time/time.h"
  14 #include "base/tracking_info.h"
  15
  16 namespace base {
  17
  18 // Contains data about a pending task. Stored in TaskQueue and DelayedTaskQueue
  19 // for use by classes that queue and execute tasks.
  20 struct BASE_EXPORT PendingTask : public TrackingInfo {
  21   PendingTask(const tracked_objects::Location& posted_from,
  22               const Closure& task);
  23   PendingTask(const tracked_objects::Location& posted_from,
  24               const Closure& task,
  25               TimeTicks delayed_run_time,
  26               bool nestable);
  27   ~PendingTask();
  28
  29   // Used to support sorting.
  30   bool operator<(const PendingTask& other) const;
  31
  32   // The task to run.
  33   Closure task;
  34
  35   // The site this PendingTask was posted from.
  36   tracked_objects::Location posted_from;
  37
  38   // Secondary sort key for run time.
  39   int sequence_num;
  40
  41   // OK to dispatch from a nested loop.
  42   bool nestable;
  43
  44   // Needs high resolution timers.
  45   bool is_high_res;
  46 };
  47
  48 // Wrapper around std::queue specialized for PendingTask which adds a Swap
  49 // helper method.
  50 class BASE_EXPORT TaskQueue : public std::queue<PendingTask> {
  51  public:
  52   void Swap(TaskQueue* queue);
  53 };
  54
  55 // PendingTasks are sorted by their |delayed_run_time| property.
  56 typedef std::priority_queue<base::PendingTask> DelayedTaskQueue;
  57
  58 }  // namespace base
  59
  60 #endif  // BASE_PENDING_TASK_H_